If you have ever suffered a stuck or very slow fermentation or tasted off-flavors such as harsh alcohol or butter in your beer, it could be down to the health of your yeast.
Yeast is a critical ingredient in the brewing process, as it is responsible for converting the sugar in the wort into alcohol and carbon dioxide.
However, yeast needs certain nutrients to perform at its best, and sometimes there may not be enough nutrients in the wort.
High-gravity beers (anything with an OG of over 1.070) or beers that use adjuncts, in particular, will normally need extra yeast nutrients added.
Do you need to add a yeast nutrient to all beer fermentation processes? If not, which type of wort for beer should include a yeast nutrient?
And if you don’t have any access to a yeast nutrient, what are the best yeast nutrient substitutes you can use in homebrewing? Let’s find out.
Why Does Yeast Need Our Help?
You would think with fermentation happening naturally since the beginning of time, it would be capable of finding its own sources of nutrition and not need our help.
Well, a few seismic changes in the way we harvest our yeast and crops has led to a nutrition deficiency, which means yeast often doesn’t perform as well as it should.
Yeast is a fungus, which has one job- to find sugar and then consume it. Sugar and yeast have been cohorts in the simple process of fermentation ever since they first met.
Although sugar provides the fuel for the yeast, many of the other nutrients it needs for fermentation come from the plant or grains it’s fermenting.
It’s probably by pure accident that we discovered wine and even beer by finding some already fermented fruit.
As humans discovered the fermentation process, we began producing a wide variety of delicious beverages such as beers, meads, wines, and ciders, in addition to other fermented goods such as bread, yogurt, and kombucha.
So why, if nature was capable of producing its own fermentation and feeding the yeast itself, do we need to give it a helping hand and extra nutrients?
Two reasons: the scientific discovery of yeast cultivation along with the subsequent development of yeast production in the 1800s, and the modern agricultural methods of the last few hundred years.
Instead of using native wild yeasts in familiar environments, brewers now generally use cultivated, mass-produced yeast in foreign environments, which may require greater incentives and coaxing to work and also be missing some of its usual nutrients.
Modern farming techniques have also removed many of the vital nutrients yeast needs from the crops it ferments.
There are no longer the same healthy amounts of magnesium, nitrogen, B vitamins, or Zinc needed by the yeast in the soils as there used to be.
The use of pesticides and toxic chemicals in modern farming not only kills pests but can also destroy a lot of the nutrients needed by yeast.
What Nutrients Does Yeast Need?
Yeast requires a variety of nutrients to carry out the fermentation process. These nutrients include:
- Carbohydrates: Yeast needs a source of carbohydrates to convert into energy for growth and reproduction. In beer brewing, carbs come from malted grains or other sources of fermentable sugars.
- Nitrogen: Nitrogen is essential for yeast growth and protein synthesis. Yeast requires both organic and inorganic nitrogen sources, such as amino acids, peptides, and ammonium ions.
- Vitamins: Yeast requires several vitamins, including thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), folic acid (B9), and biotin (B7). These vitamins are important for the health of yeast cells, cell growth, and metabolism.
- Minerals: Yeast needs several minerals, including magnesium, potassium, calcium, phosphorus, sulfur, and zinc. These minerals are important for enzyme function and cellular processes.
- Oxygen: Yeast also requires oxygen to carry out aerobic respiration, which is important for building cell membranes and synthesizing important molecules (this is why we often aerate the wort before pitching the yeast.) However, too much oxygen can inhibit yeast growth and lead to off-flavors in the beer.
What Is a Yeast Nutrient?
Yeast nutrient is a compound of various vitamins, minerals, and amino acids that yeast needs to grow and reproduce. It is typically added to the wort at the beginning of the fermentation process.
Yeast nutrient helps to ensure that the yeast remains healthy throughout fermentation and produces a clean-tasting beer. Basically, it’s a multivitamin for yeast (or fertilizer if you prefer).
Below, we look at some of the more common compounds found in commercially produced blends of yeast nutrients before looking at substitutes you may have in your home.
A common ingredient found in many yeast nutrients is Diammonium Phosphate, which is a salt that acts as a source of free amino nitrogen (nitrogen-delivering amino acids), or FAN for short.
Yeast needs nitrogen for the healthy growth of yeast cells which aids in fermentation. Most yeast nutrient blends will use nitrogen-based yeast nutrients.
Phosphorous is an element that is necessary for the production of energy for yeast and other important cellular functions.
Some malts used in the brewing of beer will already have nutrient-rich ingredients and large amounts of FAN, so this essential nutrient may not be needed as much, especially in 100% malt recipes.
Zinc, an organic compound that is often added to yeast nutrients, normally isn’t found in malt or grains.
Any presence is lost in the lautering, so even if you’re not using a yeast nutrient, it is worth adding some extra zinc to increase the cell count and aid yeast metabolism. Zinc is an essential nutrient for healthy yeast.
Magnesium is another mineral in yeast nutrients, as magnesium aids yeast metabolism, too.
German brewers who had to abide by the Purity laws of the Reinheitsegebot (and technically weren’t allowed to add any mineral salts) often found ingenious ways of adding zinc to their beer for healthy yeast production.
This could range from zinc fittings inside the kettle or lauter tun, zinc chains that would attach to the paddles in the mash mixing pot, or hiding a block of zinc in the brewery and occasionally taking some shavings.
Yeast Hulls, which are basically dead yeast cells, can be a source of lipids and fatty acids found in some blends of yeast nutrients that are required for new cell production by the yeast.
Of course, dead yeast cells are something you may already have at home, which can be used as a yeast nutrient substitute.
Vitamins, Thiamin, and Biotin, which are needed for cell growth and reproduction of the yeast in fermentation, are often added to yeast nutrients as well.
What Can I Substitute for Yeast Nutrients?
There may be times when you can’t track down a commercial form of yeast nutrient or perhaps you just forgot to buy some when stocking up for the latest brew.
For instance- it’s a brewing day, and your recipe calls for additional dosages of yeast nutrients and you haven’t got any. So, what do you do?
Look in your kitchen. You probably already have many excellent yeast nutrient alternatives. Here are some of the things you may find in your kitchen cupboards or the refrigerator which can boost the activity of yeast:
- Orange or lime juice
- Strong black tea
- Bread yeast, which has been boiled in water to kill off the yeast cells
- Grape nuts boiled in water
- Rolled oats, which have been boiled in water
- Ripe bananas that have been mashed, boiled, and strained- the liquid added to your wort.
Brewers Yeast as a Yeast Nutrient Substitute
Brewers yeast, a natural byproduct of the brewing process, is one of the best forms of yeast nutrients and is even used as a supplement for the human body.
Brewers yeast nutrient is a rich source of minerals and includes B-complex vitamins, protein, selenium, and chromium, which is an essential trace mineral that can help the body to maintain normal blood sugar levels.
Brewers yeast is made by extracting the brewing yeast from a beer once fermentation is complete and then drying via rollers.
Often, the brewer’s yeast will be debittered for human consumption, but you should always try to use the traditional brewer’s yeast where possible, as this will contain more of the minerals needed for fermentation.
As the name suggests, brewers yeast is added during the fermentation step process of beer and there is no need to add any extra yeast nutrients. The brewer’s yeast will normally be strong enough and have enough nutrients to carry out the fermentation at your desired rate.
However, certain beers may call for a less common yeast species, especially lagers that will need a bottom-fermenting yeast, while all brewer’s yeast tends to be made from the leftover Saccharomyces cerevisiae yeast of an ale.
Can I Make My Own Yeast Nutrient?
Yes, rather than buy a commercial blend of yeast nutrients, you can make your own mixture of nutrients for yeast, which can be stored in your refrigerator for future brews.
Below, I list the ingredients along with a step-by-step guide to making your own homemade yeast nutrient:
Ingredients for a Homemade Nutrient
- 2 liters mineral water (try to choose one with higher levels of magnesium)
- 1 cup whole wheat (cracked or rolled)
- 1 cup whole oats (cracked or rolled)
- 1 cup raisins (diced or crushed)
- 1 cup whole barley
- 1 cup banana complete with peel (diced)
- 1 cup diced tomatoes (fresh or canned)
- 1 strong black tea bag
- Add the tomatoes, wheat, oats, barley, raisins, and banana to a large pot with 2 liters of water.
- Bring to a boil over a high flame and maintain a rumbling boil for 10 minutes.
- Over a low flame, allow the mixture to simmer for 30 minutes.
- At the end of the simmer, turn the flame off and add the teabag to the mixture.
- Allow to sit for 30 minutes before removing the tea bag and continue to cool the mixture for another hour.
- Filter the liquid into a clean sanitized container using a strainer and then refrigerate.
The yeast nutrient mixture can be kept in the fridge for several months and added to your wort whenever you need a yeast nutrient substitute.
It should be added at the start of fermentation along with the yeast and at the rate of one tablespoon per gallon.
Is Lemon Juice a Yeast Nutrient?
The juice of any citrus fruit can be added to your wort as a yeast nutrient substitute, but lemon juice particularly excels due to its high levels of citric acid.
Can Raisins Be Used as a Yeast Nutrient Substitute?
By themselves, raisins are not a yeast nutrient substitute. They are often used in homemade mixtures of yeast nutrients, but when used alone, they don’t contain enough to make a significant impact.
Is Tomato Paste a Yeast Nutrient Substitute?
Some people swear by tomato paste to fuel their yeast. While it does contain plenty of nitrogen needed for the yeast to grow and reproduce, it doesn’t contain enough sulfur or phosphate to be a good replacement for Diammonium phosphate.
Do Yeast Nutrient Substitutes Change the Flavor of Your Beer?
Yes, but normally for the better. Yeast nutrients and their substitutes not only provide the fuel (which helps the yeast produce alcohol and carbon dioxide during fermentation) but also contain certain compounds that can affect the flavor.
Compounds such as amino acids, fatty acids, sterols, enzymes, and other compounds can provide the building blocks for more complex molecules that can contribute to flavor characteristics such as maltiness, toastiness, and hop aroma.
Is Yeast Nutrient Necessary?
Most all-malt enthusiasts or full-grain brewers would argue that a beer brewed with nutrient-rich grains shouldn’t need a yeast nutrient substitute added. The grains should produce enough nutrients when mashed to promote healthy yeast production in the wort.
In general, when you are brewing a beer with a wort that is made from 100% malt or all-grain, you shouldn’t need to add a yeast nutrient, although adding one tablespoon of yeast nutrient per gallon certainly won’t hurt.
However, as we saw earlier, modern farming techniques mean grains today often aren’t high in essential nutrients such as nitrogen as they should be, and different types of beer may not produce enough nutrients during the fermentation.
Do High Gravity Beers Need Yeast Nutrient Substitutes?
All yeasts have different tolerances to factors like temperature, and perhaps most significantly, the levels of alcohol.
High-gravity beers produce more alcohol as a result of rapid fermentation, and if the alcohol exceeds the tolerance limit of the yeast, it can become difficult for the yeast to handle the stress. Fermentation may stop, get stuck, or slow down with off flavors produced as a result.
In such cases, you can use yeast nutrient substitutes at the start of fermentation to ensure the yeast gets all the nutrients it needs.
Do Adjunct Beers Use Yeast Nutrient Substitutes?
When a beer contains a high level of adjuncts, then you will need a yeast nutrient or substitute.
For example, if plain sugar is used as an adjunct and is responsible for 25 percent or more of the fermentation, the yeast won’t get sufficient nutrition for a healthy fermentation.
Sugar may be the fuel of yeast, but it also lacks the real nutrients needed to promote the development and reproduction of yeast cells.
Yeast Nutrient Substitutes – The Final Call
Choosing the right yeast nutrient substitute can often save the flavor of your beer, as it helps provide all the nutrition your yeast needs for a healthy fermentation.
When you are new to brewing. you may not realize the importance of a yeast nutrient as a rich energy source for your yeast.
Without this nutrition, the yeast won’t develop or reproduce properly and may even die. This will subsequently affect the crucial fermentation of your beer.
As many homebrewers cannot find or locate yeast nutrients on demand, it’s key to note that there are many yeast nutrient substitutes you probably already have in your home.
We have looked at the most popular yeast nutrient substitutes above, and once you are confident you know everything about yeast nutrients and their possible substitutes, you can add them to almost any beer for a healthy fermentation and better flavor.
Any of the options we looked at will provide more than enough nutrients for your yeast to get the job done and provide you with a delicious batch of beer!